


Here to Stay

by Rush_Toward



Category: Undertale (Video Game)
Genre: Anal Sex, Begging, Blow Jobs, Come Swallowing, Cunnilingus, Dirty Talk, Double Penetration in Two Holes, Ecto-Genitalia (Undertale), Ecto-Tongue (Undertale), Ecto-Vagina (Undertale), Fontcest, Foursome - M/M/M/M, Friends With Benefits, M/M, Mating Cycles/In Heat, Multiple Orgasms, No Romance, Oral Sex, Orgasm Delay/Denial, Overstimulation, Post-Undertale Pacifist Route, Rimming, Smut, Stomach Bulge, Sub Sans, Underfell Papyrus, Underfell Sans, Underswap Papyrus, Vaginal Fingering, cock growth
Language: English
Status: In-Progress
Published: 2017-06-25
Updated: 2017-07-07
Packaged: 2018-11-18 19:07:19
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 6
Words: 14,599
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/11296929
Author URL: https://archiveofourown.org/users/Rush_Toward/pseuds/Rush_Toward
Summary: After living on the surface for some time, Sans unexpectedly goes into monster heat. He’s ill-equipped to handle it on his own, but fortunately his counterpart from another universe offers to lend him a hand. Despite some reservations, Sans accepts, and gets more than he bargained for...Summary and tags will be updated as more chapters are posted.





	1. Chapter 1

**Author's Note:**

> Hello, friend, good to see you! Just a head’s up, this fic is purely smut without any plot. You’ll simply have to accept that all six skeleton monsters are somehow living on the surface, in the same timeline, despite it making no sense and not being explained at all. I even defaulted to the overused “monster heat” trope, since that really provides all the justification one needs to convince the characters to fuck each other’s brains out. Shame on me, I know.
> 
> So, here is the Undertale Sans x Underfell Sans/Underswap Papyrus/Underfell Papyrus pornfic I never thought I’d write. Enjoy!

“You don’t want to go?!” exclaimed Papyrus, staring down at his brother in disbelief. Having already donned his favorite windbreaker jacket, the taller skeleton monster was ready and waiting to head out for a full day of fun with friends. “But why not? Aren’t you excited to have a Saturday hang-out session with our weird other selves?!”

The “weird other selves” referred to the other two Sanses and Papyruses who they had befriended some time after reaching the surface world outside of Mt. Ebott. Although the six males shared names and a strong physical resemblance to each other, the similarities beyond that were few in number.

Standing in the doorway of his dimly-lit bedroom and clad only in a plain white t-shirt and rumpled boxers, Sans was looking particularly disheveled, even by his own lazybone standards. Clearly he was not even close to being ready to leave. One skeletal hand toyed with the knob on his door, as if fighting the temptation to push it shut between them. Instead of doing that, he smiled apologetically at his brother’s obvious disappointment. 

“Next time I’ll come for sure, but I’m not feeling too hot today. Gonna take a rain check on the hangout, bro.”

In truth, Sans was much too hot in the literal sense, particularly in his lower half, and had been for the last day. Although the early autumn weather on the surface didn’t call for the heating in their house to be turned on, Sans still felt like the thermostat was cranked up to the max. His bones were sweltering as if his blood had turned into magma, and while he’d been drinking glasses of cool water all morning long, he seemed to sweat it out at just as quick a rate.

But he didn’t want his brother to know about it. Papyrus would fuss over him, and the necessary explanation would be far too awkward. Best to use his old fallback excuse and simply pretend to be too lazy to do anything.

His brother frowned. “Okay, well, what should I tell the others? I’m sure they are also looking forward to spending some time with you!”

“Tell ‘em I came down with some bug. They can’t fault a guy for catching a cold.”

“Alright, if you insist. ...Wait!” The other monster did a double-take. “Are you actually sick, Sans? Now that I’m looking at you, you are awfully red and sweaty.”

Crap, he’d been found out. Almost, anyway. Sans was a solid actor if he did say so himself, but there was only so much that could be done to hide involuntary body functions. He hated to ever lie outright to his pure-hearted brother, but desperate times called for desperate measures. “Nah, I’m completely fine, Papyrus. You go out and have a blast with the guys, ok? I want to hear all about it when you get back.”

“Okay!” Papyrus agreed readily. “If you’re sure you’re alright, then I’ll have enough fun for both of us! Just call my phone if you need anything!”

Moments later, Papyrus was out the front door, and Sans mercifully had the house to himself. He flopped sideways onto his ratty old mattress, aiming a couple of weak kicks at the rumpled sheets that were by some miracle still attached at one corner. Who needed a nicely made bed, anyway? As long as it was relatively soft and flat, almost anything would do.

Seeking to maintain as much air circulation as possible between himself and the sweat-soaked, clinging fabric, Sans let his stout limbs sprawl out at odd angles like a chalk outline at a crime scene. Idly, he wished that he owned a hammock and perhaps a walk-in freezer to hang it in, and tried to distract himself from his physical discomfort by contemplating the feasibility of such an arrangement. Of course, it was entirely too much work for him to ever actually bother, but the idea was entertaining.

Roughly half an hour passed by as Sans tried unsuccessfully to nap, tossing and turning miserably, sitting up only to lie back down again, tormented by the uncomfortable heat in his bones. It was especially bad in his pelvis; a detail which at first had seemed innocuous but in actuality was the strongest indicator of what was really going on. His magic surged through body in almost audible pulses, like an accelerated heartbeat, making his ears ring. It took him a good moment to break out of his half-conscious stupor and notice an actual ringing coming from his cell phone on the floor. Reaching for it, he noticed with faint consternation that his hands were jittering involuntarily, and he fumbled a bit to pick up the pleasantly cool plastic device and answer the call.

“Heya.”

“Hey, heard you’re sick!”

Greeting him through the phone’s speaker was a more boisterous version of his own voice, belonging to the other Sans who now went by the moniker ‘Red’ to avoid confusion. “That sucks, man. You got medicine over there?”

“Uhh,” Sans hesitated. “Thanks, but I’m all set. I don’t need any.”

“What? Did you tell that to your Papyrus too? I’m sure he’d have been happy to buy some if you guys had run out or something. What’s up?”

Rolling over onto his back again, Sans stared up into the plain whiteness of the ceiling overhead. “It’s not a big deal; I’ll be fine. Just need some bed rest is all.”

“Uh huh. Not such a big deal that you need any medicine, but a big enough deal that you’ll miss out on bowling night. Right…”

Sans sighed. Normally he was capable of smoothly lying his way out of just about anything, but he could tell that in his present state he wasn’t able to think too straight. Besides which, a Sans could almost always spot a lie, even though a phone call. “Alright, you caught me. I’m not actually sick, but there is a reason why I can’t go out tonight. ...I’m having a heat is all. Nobody wants a grown monster humping random stranger’s legs in public, so it’s better that I stay cooped up at home for this.”

There was a pause on the other end, then laughter. “Y’know, I kinda guessed as much, all things considered, but I wasn’t gonna say nothin’. Heat, huh? The hell? Does that happen to you often? I don’t think I need to tell you, but most people don’t get heats until they’ve been romantically close with someone for a while, and as far as I know, you’re single, pal! So what gives? I mean, it ain’t none of my business, so you know what, I’ll shut my trap. But for real though, what are you gonna do?”

“I’m… gonna just take it easy I guess,” shrugged Sans into his pillow, forgetting that the other monster couldn’t see the gesture. “Wait it out. It should pass on its own soon enough.”

“Uh,” Red’s voice took on a stern tone. “I can’t really tell if you’re being serious or not. Wait for it to pass? Like in a day or two? Sans, buddy, I’m sorry to ask, but are you frickin’ retarded? Heats don’t work that way, dude. You gotta be proactive with those things.”

“Yeah, well, I had to wait for Papyrus to leave the house before I could start “being proactive”. He’s gone now, and I can’t seem to sleep, so I’ll probably just rub out one or three and see if that does the trick.”

“No, Sans, you—” There was a sigh, and a beat before Red started up again. “Sans, I’m honestly shocked at what I’m hearing. You don’t come off as the naive type. It’s crazy that I’m even having this conversation with you at all. Have you ever had a heat before?”

Frank honesty seemed most appropriate here. “Nope. This would be my first.”

“Jesus. Okay, well I hate to be Baron Badnews, chum, but unless you get another monster’s help, you’re gonna be stuck with that heat for a lot longer than a couple’a days. More like a week, maybe longer. I really hope you got some secret friend-with-benefits that none of us know about who you can call on for help, otherwise you’re in for a bad time.”

Sans blinked as he processed this news, a sinking feeling settling in his gut. “Then it looks like you were right the first time: this does suck.”

“You’re telling me that a popular guy like you’s got nobody he can call?”

“Well…” The stocky monster leisurely scratched one shin with the toes of his opposite foot. “A few come to mind who would probably be up for it, but to be honest, I can’t say the same for myself. There’s too many strings attached to that, and I really don’t want to deal with what comes after.”

“Strings attached? Sheesh, what strings? Just make it clear from the get-go that you’re only lookin’ for tail because of your heat. You gotta be more assertive with people, Sans. Don’t be so concerned over how they feel about things.”

“Using others when it suits me just isn’t my style, Red, especially when I wouldn’t be willing to return the favor.”

“Mr. Nice Guy over here, putting everyone else first. You’re not leaving yourself many options. Okay, new idea. How about this?”

“What?”

_“This.”_ He could hear a smile in the other’s voice. “Me. If you want, I can come over there and give you a full-service, no-strings-attached solution to your heat problem.”

“Uh…” The thought honestly hadn’t even occurred to Sans, and he was a little taken off-guard by his double’s bold suggestion. “Really?”

“No I’m just jerkin’ your chain, Sans. Yes, really! You think I throw out this kinda offer as a practical joke? Listen pal, us Sanses need to look out for one another. I like you, and I wanna help you in your time of need. Say yes already.”

Sans blinked, answering spontaneously. “Alright, yeah. As long as you’re sure.”

“Hahaha, right on. Okay so here’s the deal. You’re still at home, right? I’m coming over there in a lil’ bit. Gonna see what I can work out to keep your bro away from the house while we do this thing.”

The phone call terminated abruptly; Red not being one for niceties, and Sans was left alone to wonder what he’d just agreed to.


	2. Chapter 2

**Notes for the Chapter:**

> My heartfelt thanks goes out to all those who took the time to comment, give kudos, and bookmark this story. Your kindness motivates me to write more.

Matters only grew more complicated when Red surprised him by appearing on his doorstep with both other Papyruses in tow, wearing a smug expression like the fabled cat who had swallowed the canary. Red’s brother Papyrus, begrudgingly nicknamed ‘Edge’ due to his facial scars and preference for wearing all black, gave Sans a glare that insinuated he already knew the full story. The other Papyrus, who went by just ‘Pap’ for short, had his usual box mod in hand, inhaling one last puff of caramel-flavored vape before stashing the rectangular device away into the front pocket of his orange hoodie.

“Don’t tell me the whole gang’s here,” Sans joked uncomfortably, wondering if his brother was hidden somewhere behind the trio. “Uh, what’s going on?”

“We’re gonna play patty-cake, of course,” Red replied sardonically, pushing past Sans like he owned the place. Just the brief grazing of their shoulders was enough to send tingles running through Sans’s entire arm, and he had to suppress whatever noise he’d unwittingly been about to make. Rubbing discreetly at the point of contact, Sans stepped aside to make way for the other two skeletons to enter.

Edge strode in, grunting a sort of brutish acknowledgement in Sans’s direction, followed by Pap who just kind of slipped inside after exhaling a hazy white cloud of sweet-smelling vapor on the porch. Sans shut the front door, and in a moment of paranoid impulsiveness, flipped the deadbolt too.

Red parked himself in the center of the living room floor, eyeing Sans critically. “Thought I made it pretty clear over the phone, BUT since you ask: ‘What’s going on’ is that you’re lamentably stricken with heat, and like the nice guy I am, I generously volunteered to be your heat-partner. Ringing any bells?”

It wasn’t what Sans had meant, and he had a hunch that Red knew it. Between his heat and this unexpected development, Sans was feeling a little stressed, wanting to regain control of the situation. “Where’s Papyrus and Blue?” he asked, half-expecting the two most excitable members of their odd troupe to burst through the door—or window—at any moment. 

Meandering over towards the couch, the softer-spoken Papyrus discretely drew a few curtains closed along the way before plopping down on the lumpy green thing. “Out on a cool-dude adventure in the city,” he answered for Red, chuckling fondly. “My Sans is keeping your bro distracted while we’re here. They’re seeing some kung-fu flick in theaters and then hitting the skatepark, I think. Told them we’d try to do bowling next weekend instead.”

“So we have a few hours until he gets back,” concluded Sans, relieved but not quite at ease.

Pap grinned good-naturedly. “Actually, we’ve got a lot longer than that. I asked Sans to keep him overnight for a sleepover at our place. My bro doesn’t know the exact reason, so your secret’s still safe with us, but he kinda intuited that it was important for you to have the house to yourself tonight.”

“Hear that?” Red sniggered. “Blue’s making sure your bro won’t be showing up unexpectedly to interruptus our coitus.”

Edge scoffed in exasperation at Red’s joke and leaned against one wall with arms and legs confidently crossed, apparently adverse to sharing the couch with Pap. “I, on the other hand, never leave anything to contingency, and that’s why I confiscated his house key while he was distracted!”

“Uh, run that by me one more time?” Incensed by Edge’s brazen declaration, Sans fixed him with a steely gaze and a tight grin, standing as straight as his unsteady legs would permit. “You stole Papyrus’s house key? What if he needs to come home for some reason?”

With exaggerated movements, Edge uncrossed his limbs and held up the pilfered key between two fingers. “Stole, you say?” questioned the darker skeleton derisively. He flicked it contemptuously onto the coffee table, producing a dull clink against the polished wood. “Are your mental faculties being compromised by your heat, Sans? I had no intention of keeping it beyond whatever amount of time I took to arrive here. The key will return to its rightful owner just as soon as he comes home, and this way we can’t be caught off-guard. However, if in spite of everything there is some kind of emergency that forces your brother to come back early, then obviously you can simply unlock the door for him yourself! I trust that you weren’t entertaining any thoughts of leaving tonight, hm?”

“Uh… huh,” Sans responded, wilting a bit at the realization that his protest must have sounded very foolish. This heat business was frustrating in more ways than one, exhausting his body and tangling his thoughts. To his surprise, Edge spoke up again, much more gently than before.

“But, while I only went to such lengths because I felt it was in your best interests, I know perfectly well that outside of this unique set of circumstances there would be no excuse for what I did. You have my word that your brother will receive a full apology from me the next time I see him.”

“Thanks. That’s… that’s really ‘great’ of you.”

Edge scowled, but Sans could tell that the other monster was pleased by the complement.

Sprawled out on the couch, Pap blinked mildly. “Half expected this to turn into a fight,” he remarked. “Glad I didn’t need to hold someone back.”

“Don’t be absurd; he’s no threat to anyone like this,” retorted Edge, planting one hand on his left hip in a very Papyrus-fashion. “Except maybe to himself. How bad is it, brother? He’s been sweating an awful lot; is that normal?”

Sans turned to see Red wearing far too gleeful an expression. “Hmm, I’m no doctor, but I’d say his heat’s reaching the advanced stages. It’s lucky we showed up when we did. You notice how he’s been staring at each of us this whole time? It’s ‘cuz his head is full of nothing but dirty thoughts about what we got in store for him.”

“I think you might be projecting,” Sans rebuked dryly. He’d been thinking no such thing, or at least he hadn’t until Red brought it up. Now, though… “I’m just trying to understand why three of you came when I was only expecting one.”

Edge crossed his arms again and gave him an impetuous stare while Red looked entertained by Sans’s denial.

“My bro came along to help out. Sorry for not tellin’ you sooner, but this whole thing is kinda thrown together last-minute. I’m sure you don’t mind, right? After all, the more the merrier.”

“Figured I might be needed to counterbalance these two edgemeisters,” Pap shrugged, stifling a yawn.

“I’m almost shocked that a lazy guy like you would even bother,” said Red with a laugh.

Pap scratched the side of his head disinterestedly. “Hey, I mean, I can put in the effort when it’s for a good cause, right? This isn’t exactly an everyday thing.”

“Hmph, ‘lazy’ would rightly describe the entire lot of you!” grunted Edge, pulling a disgusted face. “You should be grateful that I came along to make sure this gets done properly!”

Somehow, the situation had become like this. In the span of just an hour Sans had gone from having zero to three heat partners. He should probably feel lucky that the solution to his problem had practically fallen into his lap through zero effort on his part, but a more cynical side of him thought that if it seemed too good to be true, then it just might be.

“Gee, are we sure all this isn’t just some kinda fever dream I’m having?” he joked lightly, soul pulsing in his chest so strongly that he worried they could hear it.

“You tell me, buddy-boy,” Red growled softly through a grin, leaning in close enough that Sans could smell a hint of Red’s favorite cheap whiskey on his breath. “Are you dreamin’, or is this real?”

The close contact was having a tangible effect on Sans, his heat-infused magic responding to the proximity of a willing monster. A shiver traveled down his spine, the strange tingle settling in his pelvis. Red continued to meet his gaze, fanged grin stretching wider at Sans’s reaction. He slid a hand around the back of Sans’s neck, feeling the minute trembling of the warm bones, and Sans subconsciously leaned into the touch.

“That answers that,” concluded Red smugly. “So, care to tell us how you want it? Or do you prefer to have someone else decide for you?”

Before he could really consider the implications of Red’s question, an important concern occurred to Sans. “Wait. I don’t have any, uh, protection.”

Edge didn’t seem to understand. “What do you mean? We can protect you from anything.”

“Contraceptives,” Pap explained on his behalf, slouching to one side with his elbow on the padded armrest. “He doesn’t want one of us getting knocked up, obviously.”

“Obviously!” agreed Edge far too quickly. “That’s a non-issue for anyone with the slightest bit of sense! Honestly, I’m insulted that you even think I need to be warned.”

“All I know is, all this talkin’ has me feelin’ restless,” said Red, drawing out the ‘s’ at the end.

“‘Restless’ he says. So impatient, brother, and meanwhile Sans is the one who’s in heat.” Edge stroked his chin in a thoughtful manner. “Hmm… Between the three of us, you jokers are the the most perceptive, so I propose that the two of you focus on making him feel good while I give him the fucking his body craves.”

“Sure thing, bro,” Red smirked, locking eyes with Sans, who's had grown wide at the news that Edge would be doing a lot more than just ‘helping’. “Can do.”

“Any objections from you, bum?” Edge shot a challenging glare at Pap.

“Mm, nah,” Pap replied serenely. “Unlike you I’m not really the high-energy type, so I think this role suits me fine.”

“Fantastic. Just remember that Sans is counting on us, so you had better not slack off, got it?!”

Pap gave a sleepy mock salute and swung to his feet, unceremoniously tossing a couple couch cushions to the floor. Kicking them into a wedge-shaped pile, he sat down and reclined against them, legs stretched out straight in front of him. “This should be good enough,” he assessed, looking up at the other three. “All set.”

“Okay, Sans,” said Edge authoritatively, turning towards the shorter monster. ”You’re going to straddle this idiot’s shoulders and kneel over his face.”

“Hey, words hurt,” Pap quipped.

“You’ll live.”

Sans remained frozen on the spot, white eyelights flicking hesitantly from one monster to the next before settling on the far wall. Despite being turned-on beyond belief, and even though he’d already accepted Red’s help over the phone, this was the moment of truth, and he was second-guessing his ability to actually go through with it. The feeling was not dissimilar to stage fright when performing at an unfamiliar venue.

“I uh…” Sans swallowed, the sound audible in the quiet of the room. Every raw fiber of his being yearned to touch and be touched by another person, but he hadn’t lost his sense of propriety just yet. “Are you sure? About, ah, all of this?”

He flinched as his double slung a friendly arm around his shoulders, leaning in so close that Sans’s heat-addled mind was temporarily overwhelmed by the warm feel of another body pressed against his. His hands balled into fists at his sides to avoid latching onto Red like a barnacle. The other skeleton smiled at him assuagingly, a hint of mischievousness shining through.

“Sans, Sans, buddy, friendo, pal. You think too much, you know that? Don’t you wanna just let someone else take the wheel for a little while, huh? C’mon, man, I know that heat must be gettin’ to ya by now. It feels pretty awful, don’t it. We’re gonna help out with that, capiche? Alls you gotta do is let us!”

Without warning, he jabbed one kneecap into the back of Sans’s leg, buckling the already wobbly joint. Sans collapsed with a muted gasp, but Pap caught him under each arm as easily as if he weighed nothing at all.

“Woah, gotcha.” Flattened orange hood framing his skull like a halo, Pap graced Sans with a patient smile. Apparently he noticed the tenseness underlying the shorter monster’s smile, because Pap’s expression softened further. “Hey, Red’s right, Sans. There’s no sense holding back now that it’s come to this. Trust us, okay? We’ll take good care of you. And don’t forget that ultimately you’re the one calling the shots here,” he told him kindly.

Sans was struck by just how different Pap could look from Papyrus—a lot less peppy, but more mature, almost older—and yet right now Sans’s soul had that same fuzzy feeling as when one of his stupid jokes earned a laugh from his brother.

Edge stalked into Sans’s line of sight. “To be clear, all this is purely casual. There is no debt to be repaid, so you can put your mind at ease.”

“Exactly,” Red agreed with a one-armed flourish. “I promised you a no-strings-attached experience for the _wonderfully momentous_ occasion that is your first heat, and despite what it mighta looked like at first, that part hasn’t changed. I’m true to my word; nothing has to be any different between us after this. Basically, you get the screwing you so rightly deserve, that heat of yours gets sent packin’ in a jiffy, and nobody outside this room’s any the wiser!”

“Wow, friendship is really something,” Sans intoned wryly, doing his best not to give away how uncommonly shy and flustered he secretly felt. “What did I do to deserve such caring friends?”

“Christ. Ok, let’s get this party started already. Go on, Sans. Do what my brother toldja.”

Sans allowed himself to be guided so that his knees balanced on the soft cushions to either side of Pap’s head, his crotch embarrassingly close to the other monster’s face. The artificial scent of caramel clung to Pap’s clothes, making San’s mouth water. It occurred to him that since he could smell Pap then it was certain that Pap could smell him too, especially when his nose was mere inches from Sans’s throbbing arousal. The thought made Sans’s skull burn pink with a sense of mortification he was completely unaccustomed to. He clenched his jaw and resisted the urge to back off and close his thighs, or worse; to lean closer so he could grind mindlessly against Pap’s face.

Apparently his stiff posture didn’t escape Red’s attention. “Don’t look so uptight, guy!” his double laughed. “I can see you still need a little convincing before we get started. Hey! That’s fine! I’m not gonna pretend like any of this is normal. Look, we’ll go slow at first, alright?”

Red got to his knees as well, as close to Sans as the pillows would allow. He tugged off his fingerless gloves and dropped them to the floor before sneaking his hands under the hem of Sans’s shirt. Hypersensitive, Sans sucked in a breath and unconsciously held it as Red’s clever fingers flit over each rib as if counting to make sure they were all there. His hands were refreshingly cool in contrast to the unbearable hotness that had been plaguing Sans, and he found himself leaning into the touch, wanting more.

“See, nothing to worry about,” Red insisted as he rubbed Sans’s rib-cage in soothing circles. “You’re gonna love this.”

Behind him, an imposing presence that could only belong to Edge drew near. The rough skeleton’s gloved hands wrapped over Sans’s shoulders and caressed the bones with surprising gentleness, steadily massaging out the pent-up tension. Meanwhile, Pap began running his palms up and down Sans’s thighs, slipping into the leg openings of his boxers but never venturing past PG-13 territory. It seemed like he was simply getting Sans used to having another person’s hands on such an intimate area, and Sans honestly appreciated the consideration. However, the gesture wouldn’t spare Sans’s modesty for long, as all the pleasurable touches were resulting in the development of a distinct moistness between his legs. Sans gulped at the thought of that wetness eventually sliding down the inside of his thighs towards Pap’s hands.

“We need to getcha out of these pesky clothes soon, hmm?” Red murmured in an unsettlingly sultry tone right next to his ear. Sans hadn’t even known he was capable of sounding like that. “Then we can get down to more serious business, heheheh.”

“Sure…” Sans agreed, swallowing down his trepidation and resolving to enjoy this to the fullest possible extent. “No time like the present.”

**Notes for the Chapter:**

> I hope it doesn't come off like the three of them are pressuring Sans into sex, but in case there's any doubt, let me be clear that these dudes really are being genuine in what they say to Sans. There's no manipulation going on here.


	3. Chapter 3

**Notes for the Chapter:**

> Smut time.  
> ...Chapters 3-7 are nothing but smut, actually.

Sans lifted his arms as Edge peeled his t-shirt over his head, tossing the damp article so that it landed neatly on the back of a chair. Sans’s boxers soon followed, and he had to fight to suppress the spike of diffidence that arose from being so exposed in front of other people.

His magic, colored a light blue with sparks of sunshine yellow, swirled around his bones, flaring up excitedly now that things were progressing. Already it had coalesced and solidified in his pelvis, filling up the hollow cavity to form a semi-translucent vulva. Sans hoped the others wouldn’t think him odd to not have a penis instead; it was certainly strange for Sans by virtue of him having only ever made female parts on one or two prior occasions for curiosity’s sake. But he reasoned to himself that it made some sense for his magic to have reacted this way, taking into consideration the fact that he had three willing sex partners who all happened to be distinctly male.

It did cross his mind that he could request for the three of them to undress as well, so that Sans wasn’t the only one so vulnerable, but he decided against it. These were his friends, not his romantic partners, and a room full of naked monsters was a greater degree of intimacy than Sans was willing to contend with. Better that everyone else remained clothed to help preserve the impersonal arrangement they’d established.

“Hey,” said Pap, winking up at him good-naturedly. “Aren’t you glad it’s just me down here with my totally normal teeth? Pretty sure no sane monster would want to be anywhere near either of these two shark-mouthed edgelords.”

Sans laughed too, but with his bare pubis and aching genitals hovering a breath away from Pap’s nonchalant smile, he couldn’t quite bring himself to look the other monster in the eye.

Red had gotten up to fetch a kitchen chair, dropping it behind Pap’s head and sitting down heavily, facing Sans. “Here, you can hang on to me,” he offered, patting his knee. Gingerly, Sans did so, taking hold of the other monster’s upper legs as he waited to see what would happen next.

Edge’s deep voice rumbled just behind him, but he didn’t turn to look. “From here on out, Sans, you can leave everything to us. If for any reason you need us to stop, all you have to do is say so, and we will. Rest assured, you’re in good hands.”

“Thanks,” said Sans as steadily as he could manage. Letting someone else take charge sounded right up his alley. “I really owe you guys one.”

“Guess that’s my cue to get started,” said Pap. The taller skeleton cupped his hands around Sans’s bare hips, gently pulling him in closer. Something soft and wet made contact with the magic flesh between his legs, causing him to jolt in surprise. He looked down to see that Pap had formed a pale emerald green tongue and was wasting no time putting it to use, licking a long, solid stripe up San’s slit from bottom to top. Holding back a moan, Sans fought not to press into the other monster, curling his fingers tighter around Red’s leg bones to ground himself.

“Mm,” said Pap with a hint of laughter in his voice, teeth grazing Sans’s clit. “Not bad. In case you were wondering, or something.”

Actually, Sans hadn’t, but he sure was now. Shoot. His magic should be perfectly clean, though the polite thing would probably have been to shower before they’d arrived. But Red hadn’t exactly given him much of a timeframe beyond ‘in a little bit’, and Sans had only barely known what was on the agenda. Oh well, too late to worry about it now, and Pap wasn’t complaining, so no harm done.

If he thought the effects of his heat were overbearing before, it was nothing like the tingly burn that danced along his bones now. Holding still proved quite difficult. Again and again, Pap’s warm tongue dragged up the length of Sans’s vulva, the velvety texture making his nerves sing. It felt strange—but so, so good—and some of the stiffness left his posture as he got more used to the experience. Slowly he began to unwind, and his eyes grew distant as he rocked gently into the invitingly soft wetness of Pap’s mouth, letting himself melt into the sensations. This was exactly what he’d needed all along, and he felt foolish for having even considered turning it down.

“That’s right,” Red growled, and Sans looked up to see his gold-toothed double grinning lecherously at him with hooded eyes. “Let it happen, Sans. Leave your problems at the door and just enjoy this. We’re going to make you feel like you’ve gone to heaven.”

Curious, Sans risked a glance over his shoulder and saw Edge watching them intently. The intimidating skeleton had his arms folded across his chest like a foreman overseeing his crew at work.

Then a gasp was wrung out of Sans as Pap’s tongue flicked against the erect little nub at the peak of his sex, over and over. For a few minutes this continued; Sans clutching a smirking Red’s thighs while kneeling over Pap as the lankier skeleton lapped at his tender folds. Little by little, Sans’s composure slipped, and Pap was gradually able to coax more soft moans from Sans with each passing moment.

All the loving attention to Sans’s clit caused it to become swollen and more receptive, eventually peeking out from under its hood. Pap caught it between his teeth, squeezing very gently and giving it a sort of kiss before switching to Sans’s inner labia. They were terribly sensitive, and Pap was able to earn a series of small, stifled sounds from Sans as he tugged on the delicate flesh, lavishing the area until Sans could no longer think straight.

Pap constantly changed up how he chose to stimulate Sans, never focused on any one spot for too long. It wasn’t enough to allow Sans to reach climax, but right as he felt tempted to complain, he realized that Pap was doing it on purpose. By now, Sans’s inner thighs were streaked with evidence of his heightened arousal, and this seemed to be exactly what Pap had been waiting for.

One of Pap’s hands migrated from Sans’s hip to between his legs, fingertips teasing at the lips of his sex. A single slender digit rolled around the outside of his slit, gathering up the slickness there, before slowly inserting up into his aching vagina. Clearly Pap had prepared him well, because the intrusion slipped in without any trouble. Carefully rocking his finger in and out a few times, Pap deemed it safe to add another.

Sans exhaled harshly at the unfamiliar stretch, thighs quivering. The combination of Pap’s tongue and fingers was making it difficult to control his hips. He couldn’t believe how right it felt to have something inside of him, and he struggled against the desire to start rutting against Pap’s mouth, not wanting to risk hurting the taller monster. With immense willpower Sans held himself mostly still, letting Pap set the pace between them.

Predictably, that pace was deliberate and unhurried. Pap’s arm moved only marginally as he felt around inside of Sans, mapping out the dimensions of his conjured sex. Fortunately he kept up the motions of his mouth over Sans’s clit and folds, licking, sucking, nibbling, and rubbing the needy flesh. Sans’s breathing picked up and his entire body began to tremble as his orgasm drew near.

“Heheheh… Somebody’s having a good time,” commented Red with a grin. “Hey Pap, you done this before or something?”

The supine skeleton paused his oral ministrations long enough to reply, “A gentleman doesn’t ask, and a lady doesn’t tell.”

“Ha!” Red barked out a laugh. “Shit, ya got me. I guess I’m not much of a gentleman, then. Though you’re not much of a lady, either.”

“I’m not, but I still know my way around lady parts,” said Pap with a soft smile. “Let’s see if I can find it…”

“Ohhh, boy,” stammered Sans as Pap switched how he fingered him, from the slow sliding in and out to crooking his fingers and pushing hard against the front wall of his vagina. Pap's long fingers easily reached his g-spot, rubbing the spongy tissue with a firm pressure that made Sans’s knees weak with ecstasy. “Oh, my god.”

“Hey, looks like you found it after all,” praised Red. “Oh he really likes that.”

Aware that he was blushing, Sans could only cling feebly to Red as Pap worked him over. The taller monster stroked his g-spot diligently while swirling his tongue around Sans’s clit. It wasn’t long before Sans felt his peak approaching.

“I… I’m gonna…” He couldn’t even form a complete sentence. Pap got the message anyway and sped up his motions, fingertips jabbing mercilessly into the spot that brought Sans so much pleasure while his tongue crushed San’s clit against his pubic bone. The rougher treatment was the final push Sans needed to finish, and he keened out loud as he came hard, eyesockets squeezing shut and his hips bucking involuntarily. Not stopping the rolling motions of his fingers and tongue, Pap eased him through it until Sans’s shudders had slowed to a minimum and he was panting softly.

“Doin’ alright?” Pap asked him in a voice tinged with affectionate laughter.

“Doing great,” Sans murmured back, head buzzing slightly in the afterglow. He could tell he was wearing a loopy smile. “Thanks a million.”

He made eye-contact with Pap for only an instant, quickly looking away upon noticing the glossy streaks of wetness smeared over the other monster’s smile; the product of Sans’s own messy release. It was an embarrassing sight, but overall Sans’s initial discomfiture had diminished by a fair margin after being brought to climax in front of an audience. His magic was now swimming with feel-good chemicals that gave him a sense of inner peace and stripped away his lingering reservations. At the same time, even after that world-shaking orgasm he could already feel his heat flaring up again, demanding an encore. It was still far from over.

**Notes for the Chapter:**

> I hope you can forgive me for going against fanon when it comes to the guys' magic colors, because that's a thing in this fic.
> 
> Let me again express my gratitude for all the support you guys have shown me. Please continue to enjoy this story, and let me know what you think in the comments!


	4. Chapter 4

**Notes for the Chapter:**

> In which my more shameful kinks start to rear their ugly heads.

“Well, I’m happy to say your performance is acceptable,” Edge directed at Pap, who ignored him. “I think it’s about time that I got started as well.”

Without further ado, Edge straddled his other self’s splayed legs, resting his weight on one arm as he hunched down. Glancing back, Sans saw that Edge had brought his face level with San’s pelvis. Pap’s fingers were still buried in his sex, but that didn’t seem to be where Edge’s attention was focused.

Sans had caught his breath enough to speak clearly. “Looking for something, Edge?” he asked playfully, soul swelling with affection for his companions. Probably it was just the hormones affecting his mood, but that was hardly a bad thing. “Didja maybe lose a contact lens?”

The darker skeleton didn’t respond. Instead he trailed one elegant finger up the conjured flesh of San’s backside, drawing a shudder and a small noise of surprised pleasure from the shorter monster. Edge repeated the gesture a little stronger with his thumb, petting him along the smooth curve of flesh while his fingers curled around Sans’s hip. His intent was unclear until he spoke up at last.

“I need you to alter this; make it a little different, Sans,” he intoned. “Give yourself an asshole.”

Edge’s crude instruction resulted in a puff of startled laughter from Pap, and Sans had similar trouble keeping a straight face. “Um, what for?” he asked, just in case there could be any other possible reason besides the obvious.

“I’m going to fuck it,” came the blunt answer, exactly as expected. “There needs to be an exchange of fluids between partners, and by doing it this way we don’t run the risk of getting you pregnant.”

Ordinarily, a skeleton-monster’s digestive tract only manifested in response to ingesting non-magical food, and Sans had certainly never summoned any single organ independent of the rest of the system. He wasn’t sure the best way to go about it, but Red seemed able to read his mind and offered some advice.

“Hey, you’ve probably eaten human food before, haven’t ya? And afterwards, you had to, y’know, go. Just concentrate on the memory of how having that specific anatomy felt. Don’t worry about any of the other organs and whatever; you don’t need all that, and it’ll just wear you out to form everything while we do this.”

Sans nodded and flexed his mental control over his magic, willing the summoned flesh in his pelvis to shift slightly in shape. A new canal extended upwards, running parallel to his vagina.

Edge hummed approvingly and swiped the pad of his thumb across the soft skin again, but this time he brushed over Sans’s newly-made anus, which clenched up in reflexively at his touch.

“Very good, Sans,” Edge praised.

Mildly humiliated, Sans buried his head in his arms, hiding from the stares of his companions as Edge continued to lavish his ass with tender caresses that felt so much nicer than they had any right to. A moment later, he felt Pap start up again as well; the digits still inside Sans teasing at the slick corrugated magic to slowly but surely rekindle his arousal. The flat of Pap’s tongue returned to his swollen clit, rubbing in gentle circles, and San’s resulting groan of rapture was muffled by the wooden seat of the chair.

Something dry and cool swept across the back of his head, and Sans looked up to see that Red had produced a black kerchief and was mopping up the beads of sweat collecting on Sans’s skull. The other skeleton seemed to be breathing a little heavier himself, his eyelights unusually large and bright.

“You have no idea how hot you looked,” Red told him. “The expression your face as you came… That was the sexiest thing I’ve seen in a long while.”

Sans blushed anew, needing a moment to process the compliment. It definitely wasn’t the sort of talk he was used to having directed at him, and he wasn’t entirely comfortable with it. Wisecracks were his go-to tactic for deflecting. “Careful, or people might start calling you a narcissist.” Very technically, they were the same monster, after all.

Red laughed, wadding up the handkerchief and stuffing it back into his inventory. He continued petting the side of Sans’s head affectionately. “And since when have we ever cared what people think of us?” he challenged. “Screw ‘em; sexy is as sexy does.”

“Can’t exactly see much from down here, but it sounded really hot, too,” commented Pap. “Is it weird of me to say that even when you sound like my bro?”

“Do I need to repeat myself?” Red shook his head, laughing in unison along with Sans and Pap.

Suddenly, what could only be Edge’s warm breath washed over Sans’s backside, and his spine straightened in shock. Perhaps miffed that Sans had become too distracted, Edge had opted to up the ante, and his next move nearly made Sans’s jaw drop.

Edge was lapping at his back entrance, warm saliva making the sensitive magical flesh tingle. Every sweep of his velvety tongue, while gratifying, simultaneously made Sans crave even more. Fortunately, Edge was willing to give that to him, dragging the flattened muscle repeatedly over Sans’s asshole. Occasionally he would switch to prodding the center of the tight ring with the tip of his tongue, dipping in progressively further to gradually encourage it to loosen up for him.

“God,” Pap groaned from below, speaking in between licks. “He’s getting so wet when you do that. It’s just dripping out now.”

Sans couldn’t help his face heating up from the vibrations of Edge’s dark chuckle against his saliva-slickened ass. It was hard to believe that the normally proud monster had no qualms with putting his mouth on such a place. “C-c’mon, you guys…” he protested halfheartedly in a voice he barely recognized as his own.

“That just means I’m doing something right,” murmured Edge, sounding very self-satisfied.

“Ahh, like you could ever do it wrong,” chimed in Red, his smirk tempered with admiration towards his brother. “You’re the greatest, Papyrus.”

The other monster chuckled again and continued rimming Sans. His motions grew more aggressive, tongue prying insistently at Sans’s entrance until finally the tip wriggled in. Sans cried out despite himself, holding Red’s knees more tightly. Edge didn’t hesitate for a even second, gripping Sans’s hip with one hand so his thumb could join in, pushing alongside his writhing tongue through Sans’s asshole. All the while, Pap continued attacking Sans’s g-spot while licking and nipping at his outer sex.

If having someone else’s fingers inserted into his inexperienced vagina was a strange and unfamiliar sensation, then a tongue up his ass was thrice as much so. Sans experimentally flexed around the fleshy intrusion and gasped when it responded by gently lashing at his insides, getting the smooth walls nice and slick. Light pinpricks of pressure against the surrounding outer flesh were a reminder of Edge’s sharpened fangs, but never did they so much as break the skin. Sans could feel a brush of cooler air kiss his exposed hole whenever Edge pulled away every so often to breathe.

“You know what this is, don’t you, Sans?” Edge asked after a while. His thumb held Sans open, digging firmly into the summoned flesh. “This is preparation. I’m getting your body ready for the real thing.”

Sans squirmed pathetically as Edge’s tongue entered him again, deeper than before. “Yeah, I... gathered as much,” he whimpered, trying not to think too hard about what came next, even though his body burned for it.

Edge’s other hand came up to wrap around San’s lower spine, gloved fingers running pleasurably over every individual bump and divot. He gripped the broad column and squeezed rhythmically, working out the last lingering traces of tension from the bone. Beneath them, Pap shifted against the cushions, lifting his head higher to more fully capture Sans’s flushed sex, creating a host of embarrassingly wet noises.

Feeling so amazingly safe, Sans practically melted into their hands. Before he realized what he was doing, Sans had begun arching his back and pushing into Edge’s mouth, wordlessly begging for more.

“Ho ho,” murmured Red, instantly noticing. “You like that, huh? Being eaten out on both sides? You enjoy having my brother’s tongue shoved up your ass? Yeah, you kinky bastard. I think you do.”

“If I didn’t know better,” Sans panted with a slight smirk of his own, “I’d think you were jealous.”

“Of you, or of them?” cackled Red, not bothering to call Sans out on his obvious deflection. “Now don’t get me wrong; there’s nothing about this that doesn’t drive me wild. But you and I both know what we are: observers. We watch and we judge. I’m more than happy with the current arrangement, ‘cuz I got the best seat in the house!”

A sudden nip at his clitoris made Sans yelp, while at nearly the same time Edge began lengthening the tongue already nestled snugly within San’s rear, reminding him yet again that despite everything they were still Papyruses, and Papyrus disliked being ignored. He groaned brokenly as the slick muscle penetrated him more deeply than should have been possible, reaching back perhaps a full five inches or so. The fact that Edge was so adept at manipulating his magical physiology was impressive, if not somewhat alarming.

A few more thrusts of that sinuous tongue later, Edge silently pulled away, and then Sans heard the jingle of a belt buckle. Pap removed his fingers as well, and Sans was suddenly overcome with nervousness.

Foreplay was over. This was really happening. Edge was going to fuck him, while Red and Pap watched. 

He considered asking them to stop, because they’d promised they would if he wanted. His heat wasn’t finished, but maybe if Pap were willing to get him off one or two more times, that would be good enough. Did saliva fulfill the requirement of ‘fluid exchange’? He wasn’t sure. A life devoted predominantly to the study of applied science, wordplay, and kinesics had apparently left Sans woefully ignorant of something as simple as dispelling monster heat.

“Is something the matter, Sans,” Edge taunted lightly. “Getting cold feet, perhaps?”

Turning, Sans caught sight of Edge with his black jeans now bunched around his thighs, belt removed, and the perfect royal-blue erection he now sported. Edge’s mouth pulled upwards at the corners into a cocky smirk when he saw Sans staring.

“But I should remind you that this is what will cure your heat, you know.” He wrapped his now-bare sharpened claws around it loosely, giving a few cursory tugs to show off.

Sans stared at the magic’s color, amazed that for all the many differences between Edge and San’s brother, the rougher monster still embodied the same integrity that was so prevalent in his Papyrus. The revelation settled matters for Sans. Nervousness gave way to relief, and he knew there was nowhere to go but forward. Taking a calming breath, Sans winked cheekily at the taller monster.

“Naw, nothing like that. Just wondering what’s taking you so long.”

Edge raised one eyebrow, smirk softening. “Really. In that case, please accept my humblest apologies for keeping you waiting, Sans. Now, if you don’t have any objections, I’m going to ravish you with this, and I won’t stop until you’re totally satisfied. How does that sound?”

“Sounds hot,” interjected Red.

“Seconded, nyeh heh heh!”

“As if your opinions are even relevant,” scoffed Edge. Still straddling Pap’s outstretched legs, he sidled closer to Sans and pulled the smaller monster up against his chest.

Sans could feel Edge’s heated length grind against the curve of his lower back, the tip daubing a small spot of wetness on his spine. The faint aromas of cured leather and fresh sweat with a hint of bone cologne enveloped Sans, and he found himself instinctively taking in deep breaths, Edge’s unique scent fueling his arousal.

“Are you ready?” Edge murmured lowly into Sans’s ear. “This is going to be more intense than anything you’ve experienced in your life.”

Soul pounding in his chest, Sans stared into his other self’s intelligent eyes. Red returned his gaze unblinkingly, saw-toothed grin slipping back into its more usual mask-like appearance as they all awaited his answer. Lower, Pap’s free hand squeezed San’s thigh lightly, and he shuddered, swallowing hard.

He wanted this so bad that it legitimately scared him.

“Yeah. Let’s do it,” he whispered, barely audible. “Just... try to go easy on me.”

“As you wish.”


	5. Chapter 5

**Notes for the Chapter:**

> This is… the filthiest thing I’ve ever written, intentionally so. Your mileage may vary; perhaps by some people’s standards this is still in the ballpark of vanilla, haha. Usually I like to compose porn that’s a bit more classy, but this time I deliberately chose words and phrasing that were really unsubtle, treading the line between arousing and repulsive.
> 
> Btw, I don’t necessarily headcanon the magical physics described in this story. It’s is just how I wanted things to work in this one particular instance. I’ll explore different systems in other lewd fics.

“As you wish.”

Edge swiftly released him and pushed the heel of one hand between San’s shoulder blades, wordlessly ordering him to bend forward. The other hand guided his dick to San’s exposed entrance, lining them up. There was a bit of a height difference between them, and Edge compensated by planting one steel-toed boot flat on the floor next to the cushions and balancing on his other knee, getting his hips down to Sans’s level.

Sans flinched as the blunt cockhead pressed insistently at his puckered opening. Edge fed it into him slowly, sliding past the thoroughly slickened entrance. Despite all the careful preparation from earlier, Sans still wasn’t ready for the overwhelming sensations that accompanied the penetration. Unable to keep silent, Sans’s voice escaped in a quavering moan which grew louder as as he was breached.

Gradually, inch by unbearable inch, Edge sank deeper inside, widening his passage as he went. Then he came to a halt, and for an instant Sans foolishly thought perhaps that was it; that Edge was fully sheathed. He was proven wrong when Edge retracted fractionally before plowing in again, this time not stopping until he’d fit his entire length into the smaller monster. Their hips came flush together as Edge finally bottomed out, packing Sans’s rectum full of hot, hard magic. Thankfully, the shaft’s surface was silky soft and forgiving against his sensitive insides, and Edge seemed content to allow Sans time to acclimate to the new feelings, choosing to hold very still inside the other monster.

Pap rubbed circles over Sans’s clit with the pad of his thumb, while the other hand returned to its place between his legs, two bony fingers worming back into his vagina. The combination of Pap and Edge stuffing his holes was almost too much for Sans, who could barely hold himself steady while trying to regulate his breathing. His head was swimming, and his soul seemed to burn more fiercely, suffusing his chest with a pleasantly numbing warmth.

Red watching him intensely. “Heh, look at you. That’s the expression of someone taking a dick up his ass for the first time. So how you doin’, buddy? Everything hunky-dory down there?”

Before he could answer, Edge thrust his hips shallowly, dick knocking into Pap’s knuckles on the reentry, jamming them hard into San’s g-spot, and he was lost. Sans gasped and uttered a broken wail as he abruptly crested, chin tucking into his chest and shoulders hunching up, convulsing almost violently in Edge’s hold. His magic contracted around Pap and Edge like a vice, spasming erratically as he came.

Perhaps caught by surprise at the suddenness and forcefulness of his orgasm, there was a noticeable delay on Pap’s part before the other monster quickly redoubled his efforts, sucking hard on the shorter monster’s engorged clitoris to prolong his pleasure, until Sans at last drifted back down from his high, trembling and gasping for air.

A bit woozy, it took him a moment to remember that he’d been asked a question, and another minute more to formulate any kind reply. “It feels… pretty amazing,” he slurred, eyelids heavy. “Two thumbs up. I’m uh, definitely feeling ‘ravished’ right now.”

“Hmm,” Edge very nearly purred, “That’s very flattering, Sans. But we’ve only just begun, so save your applause for after the show.” With that, the taller skeleton began fucking Sans at a rather lax pace, pulling Sans’s hips back to meet his thrusts halfway.

Overstimulated from his recent climax, Sans panted and winced at the foreign sensation of the thick cock cleaving him open. Usually, Sans was a one-and-done kind of guy, but obviously that went straight out the window while under the influence of his heat. He almost couldn’t believe that he was still so incredibly horny, but the others acted as if it was completely expected. Pap provided him with a measure of respite, no longer tonguing him forcefully but instead teasing and toying with his dripping folds, the fingers embedded in his vagina remaining mercifully stationary.

Soon enough, the constant rhythmic friction within his bowels started to feel less alien and more pleasurable. Sans looked forward to each successive reentry as it took the edge off the the incessant tingly prickle caused by his heat. Looking down, he could see his own magic stretched tightly over Edge like a second skin, conforming to his unique shape. Edge continued to leisurely slide in and out of his body, and after several minutes of this, Sans had caught his breath and determined that his refractory period had ended.

“You’re being a lot more gentle with me than I was expecting,” he said almost conversationally, jolting as Pap’s warm mouth engulfed his genitals again.

Edge chuckled. “Of course, I’m not a brute. You specified that I should go easy on you, and that’s exactly what I’m doing.”

“But you probably prefer sex that’s a lot rougher than this, huh?”

“My personal tastes hardly matter when this is entirely for your sake, Sans. If you’re thinking that I might be getting bored, then l can assure you that’s not the case.” Edge laughed low in his throat. “Although I appreciate the consideration.”

Red sighed and shook his head disapprovingly. “Didn’t I already tell you to stop being so worried about what other people want? Listen, there’s no need to beat around the bush. Not with us. If you want something, Sans, then just just say so!”

For a moment Sans didn’t respond, but then he glanced over his shoulder at Edge, not quite meeting his eyes. “Do it how you... whichever way you normally would.”

“Hmm?” Edge’s pace didn’t falter for even an instant. “And what makes you so sure this isn't my normal way?”

“Because,” said Sans, “You’re a Papyrus. Slow and steady just isn’t in your nature.” Well, excluding the lanky skeleton reclining below.

“Fair enough. So you want for me to be rougher with you, then? Is that how you like it, Sans?”

“No, I… I don’t even do this sort of thing often enough to really know my preferences. I just don’t want to be treated like glass, is all.”

“Interesting.” His voice sounded pleased, if not outright delighted. “Well, let no one say that I’m not accommodating! Alright, Sans, because you asked for it, I’ll stop holding back. Brace yourself, because you’re about to learn how the great and terrible Papyrus likes to fuck!”

As it turned out, Edge’s advice to Sans about bracing himself was on-point, because in the next moment Edge’s languid pace transitioned into a vigorous pistoning of his hips, practically knocking the wind out of Sans. Over and over, he pulled out until only the tip of his magic was still inside, before driving home once more. His strong hands firmly grasped Sans’s ilium, allowing Edge to more efficiently coordinate both their movements. As he thrust in, he pulled Sans closer, and as he withdrew, he pushed Sans forward again. The cock spreading Sans open was thick and hard, yet the blunt head was soft enough that Sans felt no discomfort even as Edge pounded into him like a machine. 

Edge’s style of fucking was nothing short of pure, unadulterated Papyrus. There was so much of his personality in the way he moved; confident, assertive, measured, and with practiced ease. This made it easy for Sans to surrender control of his body to the other monsters, knowing that his trust in them was not misplaced. On any other occasion, he’d only say so with a heavy dose of irony, but right now Sans was truly loving having to do absolutely nothing at all.

Sans still worried for Pap, aware that their sudden jump in speed risked harming the other monster. Heaven forbid he get a tooth knocked out as thanks for his kindness. However, Pap did an admirable job of keeping up with the new rate at which Edge was fucking Sans, staying connected with Sans without stopping his oral assault for a moment. He held his mouth open, letting Edge push Sans into him, sliding him back and forth over Pap’s waiting tongue. The cushions propping up Pap’s head served double-duty, buffering the impact of Edge’s more forceful thrusts. His hand which was still curled between Sans’s thighs moved with them easily, fingers continuing to stroke and rub inside that slippery, clenching canal. 

“Hfff… yes… like that…” Sans stuttered out, speaking to both Papyruses. His eyelights were getting hazy as he lost himself in the sensations, keeping hold of Red while learning to adapt to the brutal new pace. Sans’s sense of self was slowly wearing away under the combined efforts of the three monsters. He was eagerly anticipating the next orgasm, and the scientist in him wondered how many more would be needed to break his heat.

“God, you look good like this,” Red rasped. His own arousal was obvious, straining against the front of his shorts. He palmed himself shamelessly, making eye contact with Sans as he rubbed the sweat-soaked fabric outlining his bulge. “Don’t know what I would give to be inside you right now, filling you up and making you cum on my cock. I bet I know exactly what you like and how you like it. Just imagine. But, for right now, I just wanna see you keep getting wrecked by these guys. Heheheh, they got you forgetting your own name, don’t they? Bet you never felt anything so amazing before. Well you’re in luck, because today is far from the last time you’ll get to experience this, buddy. We’re gonna give it to you again and again, every time your heat comes around. So don’t be shy about letting us know when that happens, yeah? After all, what are friends for?”

A more sober part of Sans’s mind was appalled by the overt lewdness of Red’s words, but the only reply he could manage was a ragged moan through his teeth. It was a losing battle to try and contain his noises. Every buck of Edge’s hips wrenched a new and increasingly affected cry from Sans’s throat, and eventually he had to simply abandon all sense of shame and modesty, allowing himself to be as vocal as whatever came naturally.

The two Papyruses’ hands kept him steady and upright even as Sans was violently rocked forward and back, emptied and filled over and over. Intermittently, Pap would simply stop his ministrations, fingers stilling inside Sans and tongue leaving his sex. In the absence of any attention directed at his genitals, suddenly Sans’s entire focus was on the enormous cock massaging his insides. While he wasn’t ready to admit it, Sans was coming to greatly enjoy having something in his ass. He had to wonder if his body was just made that way, or if Edge was simply that talented. This entire situation wasn’t something that Sans would ever have imagined happening to him, but now that it had, he was strangely elated at the prospect of a repeat performance sometime in the future.

“You’re taking this easily now,” Edge observed pointedly after some time. “I think you can handle a bit more.”

Sans assumed that Edge was speaking of moving faster and more roughly, and prepared himself for a more powerful onslaught. What happened instead was that Edge’s cock swelled inside of him, making Sans yelp in surprise as it’s size increased by a slight margin. The change was subtle enough that it didn’t cause any pain, yet too distinct for it to possibly have been his imagination.

“There,” the scarred skeleton purred with evident satisfaction. “That’s not too much for you, I’m sure. We’ll continue like this, and when I think you’re ready I’ll give you some more.”

More? He meant it would get even bigger, Sans inferred with muted trepidation, muscles clamping down involuntarily around the enlarged intrusion.

“I hadn’t realized this was part of how you usually did it,” Sans choked out as Edge resumed fucking him with the larger cock. Fortunately the slickness in his rear passage didn’t seem in any danger of running out, and although Sans honestly couldn’t tell whether it was being made by him or Edge, it was doing a marvelous job of easing the friction between them to bearable levels.

“For you, I’m not holding back,” said Edge, sounding rather smug.

“So uh, am I supposed to be following your lead?” Pap inquired dully. He pulled his fingers out most of the way before wedging a third finger alongside the others, pressing inward carefully so as not to poke or pinch Sans’s delicate flesh.

Sans let out a strained noise as Pap’s three fingers crowded inside him, crooking forward to press hard against his front wall. It felt so good, Sans very nearly came right then and there. With this newest addition, Sans didn’t think it possible for anything more to fit inside his body, yet Edge soon proved otherwise. The magical penis grew a second time, and Sans groaned helplessly, his smooth walls fluttering around the broadened girth. The spike in sensation was so intense it made his mouth flood with saliva.

Edge chuckled darkly at his reaction. “You felt ready to me, but I’ll allow you another few minutes before the next jump.”

An appreciative whine built up in Sans’s throat as the faint ache of the stretch transmuted into waves of pleasure that rippled up his spine. The way the tumescent shaft ground against his sensitive inner walls was incredibly gratifying, and he knew it wouldn’t take much more to make him come. Already his breaths were turning quick and shallow, and his thighs quaked uncontrollably. Squeezing his eyes shut tightly, he tuned out everything except for the feeling of fingertips rubbing steady circles into his g-spot and Edge drilling in and out of his ass.

Just as completion was nearly within reach, something unexpected occurred.

“Stop.”

**Notes for the Chapter:**

> I'd say "don't kinkshame me" but I kinkshame myself almost daily, so what the heck, feel free.
> 
> If you enjoyed this chapter, let me know!


	6. Chapter 6

**Notes for the Chapter:**

> Whoops my hand slipped and now the last two chapters are the longest ones yet.
> 
> I feel like some parts of this are still kind of weak, so I might come back and change some stuff later.

Sans heard his own voice call out, and for a moment, he didn’t understand why. There wasn’t any part of him that wanted to stop this. He’d been so utterly engrossed in the moment, eagerly working his way towards the strongest orgasm yet. He couldn’t remember telling them to stop, but that’s exactly what they did. Everything—all the wonderful thrusting and licking and stroking and rubbing and grinding—had come to an abrupt and startling halt. Edge was stock-still behind him, buried up to the hilt, and Pap had pulled away completely, fingers now motionless. The haze of lust fogging Sans’s mind began to clear, and he looked up in confusion to see Red wearing a grin full of wicked amusement.

“Ooh, you were feelin’ real good for a second there, weren’tcha? Just a little longer and you’d’ve cum your brains out, or would have if you had any, heheheh.”

It had been Red who had issued the command, not Sans. Of course. Sans made a soft sound halfway between a whimper and a sob, clenching up around the fingers and shaft still inside him in a futile effort to obtain the stimulation he so desperately needed. The pleasure was gradually ebbing away, and the orgasm that had once been so imminent was slipping out of reach. However, Sans couldn’t muster any resentment for his partners; not when Edge laid a hand over his spine to soothe and steady him, and Pap made slow, gentle strokes up and down his thighs. Still, he must have been making a miserable face, because Red tsk’d with wry sympathy.

“Aww, don’t worry, pal; you’re not gonna be left just hangin’ like this. We just don’t want everythin’ to end so soon, y’know?”

“You guys planned this, huh?” Sans accused plaintively. The response time between the three of them was far too quick for it to not have been arranged beforehand.

Red gave a hearty laugh. “Of course we planned it! This ain’t our first rodeo, pal. There’s a method to our madness.” Apparently satisfied that Sans was no longer wound up tight as a spring, he gave a curt nod to his brother. “Alright, boys, back at it.”

The return of Pap’s mouth to his vulva, hot breath caressing his over-sensitive folds, and the sudden movement in his overstuffed asshole stole Sans’s breath away. Even breathless, he managed a low, broken groan of mindless pleasure, fingers curling tightly around Red’s knees. Once again Sans was put on the steady track towards climax, driven onward by the skillful ministrations of both Papyruses, all while Red’s keen eyes took in every little detail of his perspiring, exposed form. His initial frustration was quickly forgotten, and it didn’t take long for everything to start building up again, but then...

“Stop.”

“No!!” blurted Sans in protest, denied release right as he was approaching his peak. He grit his teeth in frustration as the other skeletons once again paused their ministrations and forced his body to settle back down. He had the urge to laugh at his own childish outburst as well as to just reach down and finish the job himself, both of which he valiantly managed to resist. “C’mon, you—you can’t just... stop like this! I’m so close!”

“Oh, we know,” Red chuckled pitilessly. “And truthfully I don’t envy your position right now, buddy. But edging you like this, it’s for a good cause. A heat isn’t gonna be quenched by just one or two flimsy orgasms. Nah, that shit can last for days if not taken care of properly, and who wants that? Nobody, that’s who. And that’s why we gotta do it like this. Bust one really, really good nut, and your heat should end pretty much immediately. Trust me, it might suck now but you’ll thank us later.”

Hanging his head in defeat, Sans happened to catch a glimpse of Pap looking up at him from between his thighs, brows knitting into a compassionate expression. He also saw that his brother’s opposite was slowly having his clothing ruined by Sans’s arousal dripping down and saturating the fabric. The realization that Pap surely knew about it yet didn’t mind brought a grateful smile to Sans’s face. Even in the midst of such erotic torment, Sans took to heart that everything they did here was for his sake.

A pattern was soon established. It was clear that Red was able to gauge with pinpoint accuracy the exact moment that Sans was about to cum, and used this to leave Sans helplessly trapped on the cusp of orgasm, unable to finish. However, Sans no longer argued nor voiced any complaints. Somewhere in his soul Sans held complete faith in Red’s reasoning, and without wasting too much thought on the subject, he chose to defer to his friend’s authority. It was easier to simply take what was given to him.

While Pap resumed the purposeful teasing of Sans’s clit and labia, Edge continued the periodical expanding of his member, incrementally adding to the magical organ’s already impressive dimensions while somehow still managing to bury the entire length into Sans’s smaller form. The flared head dragged relentlessly at his inner walls while the broad base stretched San’s rim tight as a rubber band. Every time Sans thought he couldn’t possibly fit anything more, Edge demonstrated that he still had limits they’d not yet reached.

Individually, each adjustment was truly minor, but over time they added up. Eventually there came a point where Sans began feeling a pressure that bordered on uncomfortable, every thrust of Edge’s member completely bottoming out. Edge surely noticed this, but seemed wholly unconcerned even as the elasticity of Sans’s rectum was put to the test.

“I think you can take a bit more,” he stated evenly. Something about his tone suggested that he expected Sans to object.

Sans shook his head haltingly. “I can’t... There’s no more room...” If only he could manipulate the properties of his magical physiology on the same level as Edge, there wouldn’t be any problem, but that just wasn’t something that Sans had ever bothered trying before, and he wasn’t in any state of mind to learn now.

Edge slackened his punishing pace in favor of circling his hips luxuriantly, making Sans moan quietly. “Oh, that’s where you’re wrong. What you need is to relax and let me in a little deeper. You can take a lot more than this, much more than I’m going to ask you to. Trust me, Sans.”

And the crazy thing was, he did. Edge was far more experienced in this than Sans, and he certainly had no reason to lie. If the taller skeleton monster said Sans could do it, then it was simply the truth.

With Edge’s cock digging into the soft flesh at the top of his sacrum as if sure it could go further, Sans forced himself to stop fighting against the intrusion. Panting, he concentrated as best he could, willing his body to cooperate. Then his magic shifted again, coalescing around his midsection to manifest into the necessary organ. Edge hummed approvingly and rocked his pelvis forward, his blunt glans nudging insistently at the new inner ring of smooth muscle.

“That’s it,” praised Edge, pushing a little harder. “Just relax, Sans.”

He repeated this motion several times, carefully increasing the force behind each thrust until Sans moaned embarrassingly loud as he felt some inner barrier abruptly loosen and give way. Edge’s dick popped in, breaching the entrance of Sans’s newly corporealized intestine, sliding up into his digestive tract more deeply than ever before.

“Holy shit,” Red growled, tilting his head to get a better look. “I’m honestly impressed you managed to pull that off on your first try.”

Too overwhelmed by the new sensations, Sans couldn’t respond. Tentatively, he explored the slight bump protruding from his abdomen, lightly touching the taut shimmering magic with one hand. Edge’s length had speared through the snaking passage and forcibly straightened out the natural u-bend, the bulbous head plugging up Sans’s guts. At the moment it felt neither good nor bad; it simply _felt_.

Edge sounded extremely pleased. “I said that he could do it, and I was right. I’m very proud of you, Sans. You deserve a reward for this.” Edge leaned forward, chest brushing over Sans’s spine. “I’m going to let you come,” he whispered right into Sans’s ear.

“God, yes,” Sans whimpered, a rush of warmth sweeping over him. He’d just about given up even wanting it, growing comfortable with being held captive in a perpetual state of near-climax, but the promise of release reawoke the burning desire within him, wracking him with full-body shivers, and now Sans’s sex-drunk mind could think of little else. 

“Thought we were gonna wait so that it could be finished in one final go,” Pap questioned.

Edge smiled dismissively. “No,” he asserted. “What does it matter if he needs one or two more after this? I’m prepared to give him as many as he wants.”

“Hmm, you sure you can keep it up for that long, tough guy? Actually, I’ve been wondering why you seem so, eh, unaffected by all this. Aren’t you enjoying it at all?”

Edge only smirked enigmatically, and Red snorted, his mouth quirking up at the corners.

“It’s ‘cuz he’s cheatin’.”

Sans couldn’t even begin to guess what would entail ‘cheating’ in sex, let alone in this specific situation. It seemed he wasn’t alone in that, because Pap gave voice to their mutual bewilderment.

“Cheating? Like how?”

Red looked deeply amused, and maybe even a bit proud. “He’s probably set up his magic in a way where he can’t even feel any of this.”

“Incorrect, brother,” Edge countered seriously. “It would be a hindrance and a risk to Sans’s safety if I didn’t have any tactile feedback for what I’m doing. I am able to feel everything, but my sensitivity is kept deliberately minimal. This way, I’m afforded greater lasting ability to better keep up with Sans’s libido.”

“So like I said, he’s cheating.”

“Woah, that is cheating!”

“No it’s not!” countered Edge hotly, the argument causing him to stop his movements completely.

Despite Sans’s orgasm being delayed again, he couldn’t help dissolving into laughter with the others, too entertained by the volatile monster’s outrage.

“This isn’t a competition, you clods!” Edge continued. “Cheating isn’t even possible! And that’s lucky for you, because I guarantee if it were, you’d place last even without me resorting to unfair practices. Just look at yourself; I bet you’re fatigued already just from lounging around!”

“Actually yeah,” replied Pap candidly, trying to curb his smile. “Laying here is hard work. And the sooner we’ve finished helping Sans, the sooner I can go to the bathroom and deal with my own little problem.”

Skewered as he was on Edge’s prick, and with the taller monster directly behind him, Sans didn’t have the line of sight needed to see for himself, but he assumed that Pap was referring to his own arousal, and the angle that Red’s gaze had taken was confirmation enough.

“Well why wait, when I could just lend you a hand?” Grinning, Red spread his palm open in the air. With a small flash of light, a glowing copy of his hand split off to the side, hovering nearby. The magical construct flexed its five fingers in tandem with Red’s movements. “I think we both know you won’t be disappointed.”

Pap hummed into Sans’s crotch, quirking one eyebrow. “That’s pretty gay, dude. What makes you think I want you to jerk me off?”

“What makes you think I won’t make you love it?”

“I have a better idea. Why don’t YOU hold on to Sans so I can take care of myself?”

Red chuckled and shrugged guilelessly, the magic hand mirroring the gesture before flickering out of existence. “Gotta point out a flaw in your plan there, bud. Floating hands aren’t the best for holding things steady.”

“Ugh, will you two drop it already! Listen, I am more than capable of supporting Sans alone. If you don’t want my brother’s assistance and you really can’t bear to wait, then I’ll grant you permission to attend to yourself now.” Edge tightened his grip on Sans’s hips. “But remember—”

“Say no more, Bossman. I won’t forget that Sans is our top priority,” said Pap, giving Sans an almost apologetic lick. “I’m gonna take you up on that, but nobody worry; I won’t throw in the towel until Sans says we’re done.”

“What a trooper,” Red snickered. “Papyruses sure have impressive stamina.”

“Not this one,” Pap muttered. “I just don’t like to leave a job only half-finished.”

“Finally something we can agree on. Come on, then.” With astonishing strength, Edge lifted Sans off his dick and drove into him anew, thick cock boring into him relentlessly. Sans jolted and shouted in surprise as it rammed into the bend of his sigmoid colon, but his magic yielded easily, flexing to allow Edge to enter more deeply.

“Ohhh man…” Flushed and gleaming with fresh sweat, Sans exhaled vocally, still hanging onto Red for dear life. Daring to glance down and see how far inside him Edge’s dick reached, he was amazed to discover that while it was certainly a cock to be reckoned with, it wasn’t half as huge as it felt. What was incredible though was the rhythmic way that the magic occupying his abdominal cavity bulged outward every time Edge pushed into him fully. Seeing the deformation come and go with their movements was both hypnotizing and grotesque, and watching it gave Sans a peculiar sense of accomplishment. It was a visual reminder of how much he’d successfully taken.

“Pretty freaky,” he remarked flatly. “Like an alien burster...”

Red sputtered at the morbid observation. “Haha, woah, dark! Don’t worry, man, it ain’t gonna bust outta ya!”

Sans blinked at his alternate self owlishly, slowly realizing he’d spoken out loud. He twitched when Edge again leaned in close, the warmth of his larger body feeling nearly cool compared to Sans.

“You’re safe, Sans. None of this should hurt.”

“I know,” Sans murmured, his eyes hooded. “Thanks.”

The rougher skeleton didn’t move at the same brutal pace he’d set earlier. This was more disciplined and mindful, each methodical thrust encountering less resistance as the slick passage was reamed successively wider. The sensation was significantly more muted higher up in his abdomen; the flesh there much less sensitive, but his spread-open asshole was warmed from the constant friction created by their joined movements.

Sans noticed that Pap’s technique changed when he was at last free to indulge in his own pleasure. In spite of whatever fatigue Pap might have been feeling, once his his free hand left Sans’s thigh to dip under the hem of his own cargo shorts, Pap’s mouth returned to his sex with a ferocity that left Sans breathless. The easy-going monster laved unflaggingly at the puffy blue folds, paying special attention to his pulsating clit, sucking so tenderly that Sans’s eyes pricked with tears. Nibbling and licking, his tongue seemed to be everywhere at once, practically devouring Sans. Meanwhile his three fingers kneaded dutifully at San’s front wall, seemingly in sync with his own strokes to his still clothed erection.

“Holy-” Sans choked, momentarily going cross-eyed at the sheer intensity. He was quickly reduced to incoherency, the noises coming from his mouth taking on an almost animalistic quality as repeated thrusts forced the curved angle of his bowels to unfold in order to accommodate the stiff shaft that so thoroughly plumbed his depths. He was capable only of making harsh grunts and strangled cries as he was fucked and sucked, all while a mantra of _‘yes yes yes yes’_ looped incessantly in his head. Pap’s mouth and fingers felt so _good_ , Edge’s hands wrapped around his hips felt so _good_ , the immense fullness in his belly felt so _good_ , and somehow having Red’s eyes on him the whole time made everything even better. It wasn’t that Sans was an exhibitionist; it was that he’d never realized what a difference it could make to feel so _wanted_ and _cared for_.

“Come, Sans,” growled Edge as he drilled deeper and deeper into the smaller monster.

“Do it,” Red joined in, his expression enthralled. “Go on, Sans, do it.”

And he did. At last, Sans’s orgasm swept through him like a tidal wave, temporarily stopping his breathing and making his mind go blank, filled with nothing but blissful white. All of the pent-up pleasure that they’d poured into him was finally released, and the force of it was nearly _crippling_. He came silently, unable to utter a single sound, and when his trembling arms collapsed beneath him he could only lay limply with his face cradled atop Red’s knees, gasping for air.

Pap extracted himself from between Sans’s legs, leaning a bit to the side to breathe. “Trying to drown me, Sans?” he teased, licking his teeth audibly. “Whuh-oh, I think he’s running out of juice. Uh, I mean stamina.”

Sans didn’t respond, too preoccupied with counting the multitude of tiny white stars floating in his peripheral vision. He could tell that his heat hadn’t disappeared just yet, but for now he needed to take a moment to recover.

“Typical Sans,” Edge scoffed, not unkindly. His thrusting had slowed to a stop, allowing Sans to rest while Edge’s hands stroked along the overheated bones of Sans’s pelvis and spine. “I suppose it was expecting too much that you could keep up with the Great and Terrible Papyrus. What should I do with you now?”

“I got this, bro, don’t you worry,” said Red. “Keep hanging on to him for me though, alright?” Red grinned and turned Sans blue, reversing the effects of gravity. Sans made a small sound of alarm and scrambled to hold onto Red’s chair as the world shifted for him alone and he began to fall up towards the ceiling. Fortunately Red lay a hand on his shoulder while both Papyruses retained a firm grip on his lower half, Pap’s fingers inadvertently digging even harder into his g-spot.

“Bit extreme, don’t you think?” asked Pap blandly.

“What, I’m helping. If he can’t hold himself up, then you guys can just hold him down.” Red leered at Sans. “Speaking of ‘down’, while I gotchu here, darlin’, maybe you can do me a solid and go down on me, huh? Put that big mouth of yours to work?” He freed his trapped erection, pulling it out his fly, and gave it a few tugs from base to tip, twisting the head on the upstroke.

Sans simply stared at the solidified magic for a moment, recalling Edge’s earlier comment about Red being impatient. Indeed, the bright yellow that represented an individual’s sense of justice was strongly prominent in Red compared to Sans, with hardly a trace of cyan to be seen. It truly highlighted the differences that existed between them, and as if that weren’t proof enough, Red’s other hand had moved to cup the back of his head, wordlessly urging him to comply.

“Sans, I’m beggin’ ya, don’t leave me hangin’ like this. Watchin’ you has me riled up like you couldn’t believe.”

Although he had never engaged in fellatio before, Sans decided he didn’t find the idea entirely disagreeable. And so he dutifully opened his mouth, materializing a tongue of his own and running it along the underside of Red’s twitching length. Hazily, he thought to himself that it was good that Red’s dick was a much more manageable size than Edge’s.

“Ahh yeah, that’s more like it,” the other monster groaned gratefully. “You don’t even gotta do much; I’ve been about to explode in my pants for the last ten minutes. Lemme cum in your mouth, Sans, _please_. I want to see you swallow my load. C’mon, I need you bad.”

Sans squeezed his eyes shut and granted Red’s wish, taking as much of his dick into his mouth as he could manage and sucking for all he was worth. Tongue swiping along the underside of the swollen shaft, it only took another minute until, with a hoarse shout, Red latched onto Sans’s skull, bucking his hips rudely into the other monster’s face. Sans swallowed convulsively, trying not to choke on the salty fluid pouring down his throat. When Red released him and slipped out of his mouth, dick vanishing into thin air, Sans let his tongue dissipate as well, lacking the energy to maintain it. Coughing a bit, he looked up at Red with brows furrowed uncertainly. 

“Hey… shouldn’t that… have done the trick?” he asked weakly, disoriented and still feverish. It was a vaguely-worded inquiry, but Red apparently understood just fine.

“Doesn’t work that way, sweetheart. Ingesting it won’t do anything for your heat.” Clutching at the hem of his sleeve, Red scrubbed an arm across his damp forehead. “Also, you’re forgetting that we’re the same monster. The genetic material needs to come from someone else. Heh, we found out both those little details for ourselves just a couple months ago, huh, Stretch?”

“So much for keeping that a secret,” Pap sighed. “Though I guess as far as Sans’s concerned, it’s not a cat I mind letting out of the bag.”

Sans blinked in surprise. No wonder the three other monsters were so comfortable working together under such circumstances, if they’d had experience with each other already. He wasn’t sure how to feel about it, and didn’t press for details.

“This time,” said Edge in a husky voice, “my efforts won’t be wasted.” One hand migrated from Sans’s hip to up and around his chest. “Sans will be cured after I cum way up in here, where it’ll be the most effective.” His fingers brushed over Sans’s sternum and ribs, trailing south to palm the magic in his abdomen where they were connected. Being touched both inside and out elicited a weak whine from the shorter monster.

“Well how about you quit showing off and just do it already?” Pap frowned. “Sans is getting tired, dude.”

Pap sure wasn’t one to mince words. It was true that Sans was fatigued. His bones glistened with a sheen of sweat, and his joints felt like they were made of jello. Even with the protective padding of the cushions, his kneecaps were a bit sore due to the pressure of kneeling for so long.

Sans wouldn’t describe himself as a sexually active monster, especially the ‘active' part. This was by far more time and effort than he had ever invested into any instance of sexual activity, with others or alone, and having climaxed three times in the span of what he estimated to be barely an hour, his stamina was very nearly depleted. There was also the likelihood that in his weary state, the next orgasm would take longer to build up, and he worried slightly that his body couldn’t manage it. On the bright side, one more would almost certainly be enough to end his heat, just as the others anticipated.

Edge stroked a large hand up and down Sans’s spine. “Nyeh heh heh! You think I’m trying to impress anyone here? Consider the possibility that what I want is to see you lazybones finally giving 100% to something for once! However, I’ll concede that it’s about time we wrapped things up. What do you say, Sans?” The taller monster tilted his head, trying to meet Sans’s eyes. “Are you able to endure one final round?”

“I…” Sans’s voice broke, and he swallowed, starting over. It wasn’t an option to stop now, not with the heat still raging through his bones. “Sure. Show me what you got.”

**Notes for the Chapter:**

> Obligatory disclaimer: I definitely don’t endorse the kind of sex happening in this fic. There’s a lot of potential dangers to putting stuff in your butt, guys. You only get one body, so treat it with care!
> 
> Thanks again to everyone who has left kudos and taken the time to comment on my gross story.


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